Composition for preventing corrosion of metal



United States Patent 9 COMPOSITION FOR PREVENTING CORROSION F METAL Patrick J. Keating, Jr., Scarsdale, and Theodore C. Heisig, White Plains, N. Y., assignors to The Texas (Iompauy, New York, N. Y., a corporation of Delaware No Drawing. Application June30, 1954, Serial No. 440,526"

8 Claims. (Cl. 106-14) The present invention relates to protecting metal bodies against corrosion, especially the inner surfaces of tanks and vessels. More particularly, it is concerned with applying and maintaining an adherent protective coating to the interior surfaces of ballast tanks and the like formed of ferrous materials and subjected to the corrosive effect of air and water, particularly salt water. Other tanks which may be protected by the invention'are cotfer dams, bilges, voids, rudders, dry docks, and fire tower water tanks. 4

In accordance with the present invention, an effective rust preventive coating is applied to the interior walls of the vessel, tank or container as a fluent composition comprising a relatively viscous petroleum residuum from a naphthene base crude oil, a relatively fi'uid' light petro leum oil, and a small quantity of surface active agents effective to increase the penetration and adli'e'sivity' of the composition to solid surfaces and reduce corrosion.

Although the composition can be applied in any desired way, as by brushing or spraying,- it is preferred' to apply it by flotation t'orthe' interior wallsof tanks. The

composition advantageously isflOatedupon the'surface of a body ofwa'ter as' a,uniform layer. of substantial thickness and the water level is thereafter progressively altered, leaving a uniform protective coating strongly the surface layer of composition introduced, and the water thereafter drained toeffect'surfa'ce' coating. Sometimes several passes of the coating material up and down may be required for'the initial coating.

Surprisingly, our novel fluent coating material repels the surface' moisture' and bonds with the interior surfaces of thevessel reform" a highly adhesive film' which remains continuously? in plac'e'in spite of repeated draining and refilling of the tank and violent" a itation of" its contents. Since contact of Water or atmosphere "ice the ferrous surfaces is effectively prevented by the resultant coating, the objectionable rusting or corrosion which otherwise takes place in vessels of this character is effectively overcome.

The floating procedure of the present invention is of particular advantage from the standpoint or obviating the high cost and diffi'culty of applying a rust-preventive coating to the interior of a tank. The complex interior structure of ship ballast tanks, for example, made forn'rer manual procedures economically undesirable because staging had to be built for men to work on. Moreover, because of obstructions such as ladders, gussets, frames, and bafiies which hinder the workers, it has been diflieult by such manual means to obtain a uniform coating over the entire interior surface, even where these surfaces are first prepared by chipping or sand blasting. Accord ingly, exposed spots, cracks or thin areas tend to initiate points of rapid corrosion.

In ship ballast tanks or the like a small residual quantity of coating material may be permitted to remain on the surface of the ballast water within the tank, and relatively small amounts may beadded'periodically'pridr to discharging or taking on ballast, to render the protection a permanent one.

The novel fluent coating material in accordance with the present invention comprises a base composition composed of a straight run residuum from a naphthene base type of crude oil, a light lubricating distillate, and a surface active agent in the form of tall oil. To this base composition is added a small quantity of another surface active agent in the form of fatty or aliphatic diamine having the general formula:

The residuum, per se, is ordinarily too viscous to fiow readily over the surface of a body of water and is therefore thinned to the desired fluency with a suitable light petroleum stock which is miscible with the residuum to form a homogeneous solution. For the present purposes, a final composition is preferred'havinga Saybelt-Furol viscosity in' the range of about ZS-SO;

seconds at 122 F. in this range of fluency the liquid will spread uniformly across the surface of the water, making good contact with confining surfaces at its margins. thefinal composition is about 3040 seconds A suitable light petroleum stock for thinning the residuum to the desired viscosity is a light lubricating distillate having a Saybolt-Universalviscosity $109475- seconds at l0 0 E, for example 106" seconds; A dv'an} tageously, middle distillates are selectedhaving a flash point above about 350 F. to avoid fire hazard. The

A narrower preferred range of viscosity for .3 light petroleum oil desirably constitutes 55-70% of the base composition by volume.

The adhesivity increasing and corrosion preventing surface active agents preferred in accordance with the 4 low). The following coating materials were compounded and tested:

A. 33.3 volumes of a 42-45 second Saybolt-Furol viscosity at 210 F. straight run residuum from dispresent invention are tall oil such as crude tall oii obtainfining a naphthene base Crude Oil.

able under the trade name Liqro, and a fatty diamine 63.8 volumes of a nonqefinedrdistmate having a wherein the alkyl groups are derived from tallow fatty bolt Um-vel.sal viscosity of 45 seconds at acids. Such a fatty diamine contains various alkyl groups F.

having from 14 to 18 carbon atoms derived from the 29 volumes of crude u oil.

myristic, palmitic, stearic, oleic, and linoleic acids of tal- The resulting mixture had a SaYbolbFm-ol viscosity low, and has a theoretical molecular weight of 320. in of 3040 Seconds at F and a specific gravity its commercially available form the fatty diamine is a light of Q9421 at compared with Water at the red soft paste having a melting range of 44-48 (3., a same temperature.

specific gravity of 0.832, and normally contains about This composition A is m which has had Wide 80% of amine, calculated as diamine. Diamine contents mfircial acceptance as an exceptionally good mentioned. hereinafter are the actual amine contents rosion prbvbnter for ballast tanks.

CaICPIated as E P B. 99.5 parts by weight of A.

First, the talloilis dissolved in the mixture of residuum part by Weight of fatty diamine as described above and light distillate in an amount suflicient to form a base (05 pal-t Crude diamine) wherein the alkyl groups compound or mixture containing up to 5% of tall oil by are derived f tauow f tt acids volume. Then the base compound is heated to 130 C 99 Parts by weight f 7 150 F., the fatty diamine paste is heated to the same (18 part by Weight of f tt i i 0 P crude temperature, and the latter is then added with stirring to diamine) as in B. the base compound in quantity sufficient to provide an 11 98 parts by Weight f efiective corrosion inhibiting amount up to 4% by weight 16 parts by Weight f fatty i i 0 pal-ts crude of the final coating material as diamine. diamine) as in Obviously, the ingredients can be combined in other Ways within the scope of the invention, the particular HUMIDITY CABINET TESTS order not being essential to the invention.

In general, the tall oil is effective in proportions of Bright steel test panels 2 x 4 X A inches were dipped from about 15% by volume of the base compound, and in the materials under test at room temperature, allowed preferably about 24%. An amount between 0.4% and to drain for 2 hours, and suspended in a humidity cabinet 2% of fatty diamine advantageously is used. Higher operating at 120 F. with a relative humidity of 100%. percentages than 5% of tall oil and 4% of diamine are Parallel tests were conducted on panels that were dry and not disadvantageous, but are unnecessary to confer adewet with water before dipping. The panels were periodiquate penetration, adhesivity, and corrosion resistance and cally examined for corrosion and the amount of rust therefore are noteconomical. noted.

Table I Composition Hours A B O D Dry Wet Dry Wet Dry Wet Dry Wet 24 1 speck 1 speck Clean Clean Clean- 72 2specks several specks- -do do do-;--.'--- 144... num. specks num. speck do do .--.do 192. 0 d 1 speck do .--.do 240. do several specks. several specks--. -..-d0 312. 1 large spot and ..do several spots-.. .do

'num. specks. 360 do do num. spots and several specks- 4 80 several large spots num. sped-15-- mz n y gbts and do several specks. do...-.-- Do.

and 20% light specks.

ms do do num. specks do --do Do.

many specks -.--do many specks. num.specks several specksnum.specks As a result of using the tall oil and fatty diamine the The above Table I shows that the composition A novel final composition has a wetting power higher than (without diamine) started to rust after only 24 hours that of water. The highly adhesive coating material actuunder test, whereas as little as 0.4% diamine in B was ally displaces surface moisture and substitutes therefor on 5 Still p r fi P1")tection 144 6-fold the tank surfaces, 'forming'a preferential and essentially impmvementh 15% diamine i111) Provided a 22-fold permanent bond. Moreover, the described coatings actuimprovement plfotfcting 528 hours without rustingally plenetrate through rust, slime, or similar surface ac- RESISTANCE TO WATER WASHING TEST cumu ations even in the resence of moisture. This ac- Bright steel panels 2 x 3 X ,5 inches weredipped 1n the i gi i figg gfi p32115 5 53 i sg g obvlamg the materials under test and allowed to drain for 4 hours at v Va y q 1 room temperature. The panels were then immersed in nous corrosion prevention tests performed on fluent synthetlc Sea waterrfmone day followed by hanging in coating materials compounded in accordance with the i f one d hi cycle was repeated f 25 d invention clearly demonstrated its superiority over the Som panels were t ith t d th d h best compound previously known to us (compound A beclipped.

Table II Total Composition Days Days in Ex- Water posed A B C D to Air an Water Dry Wet Dry Wet Dry Wet Dry Wet 1 1 5% It. rust--.- many spots 2specks Clean Clean Clean several spots-- Clean and specks. 2 4 30% light rust. 40% light rust. .....do ..d "do .-do several large Do.

spo s. 3 6 40% light rust. --.do 2 patches, 1. patch, sevnum. large ...--d0 do 1 speck.

num. spots. eral spots. spots. 4 8 50% light rust- 50% light rust- ..do...... .do..-... several large .....do 1 patch, sev- Do.

'- patches, eral large num. spots. spots. 11 70% light rust- 60% light rustlight rust. 3% light rust-. 5% It. rust--.. several spots.. It. rust.-- 2 patches. 13 75% light rust. 70% light rust. 10% light rust. 10% light rust. 10% lt. rust num. spots, 15% light rust. 5%light rust.

spec s. 18 85% lt.-mod. 80% lt.-mod. 70% light rust. 50% light rust. 40% light rust. 10% light rust- 20% light rust. 20% lightrust.

ru ru 21 85% mod.rust. 80%mod. rust. 75% lt.-mod. 60% lt.-mod. 50% lt.-mod. 40% lt.-mod. 25% lt.-mod. lt.-mod.

ru rust. rust. rust. rust. rust. 25 85% mod. rust. ....do 80% mod.rust. 70% mod. rust. mod.rust 50% mod.rust. 25% mod.rust. 45% mod. rust.

Again the remarkable superiority of compositions B, C, and D (0.4-1.6% diamine) is demonstrated over composition A containing no diamine.

4% SALT SPRAY TEST WATERv DISPLACEMENT AND WATER STABILITY TEST Test panels 2 x 3 X ,5 inch were formed of carbon steel, sandblasted, and cleaned thoroughly. Fifty cc. of the material under test were placed in a 125 cc. flask, 5 cc. of distilled water added, and the mixture thoroughly 30 shaken. The stoppered flask was stored overnight at 130 F. and then cooled to 77 F. for testing.

Each test panel was dipped in distilled water momentarily and drained in a vertical position for not more than 3 seconds with the lower edge on blotting paper.

Table III Composition Hours A B C D Dry Wet n 7 Dry Wet Dry Wet Dry Wet 100% heavy rust- 100% heavy rust- 85% mod. rust..- 10% mod. rust.. mod. rust. 20% mod. rust. 25% mod. rust.- 40% mod. rust. 95% heavy rust. 70% heavy rust. 95% heavy rust. heavy rust. 85% heavy rust- 85% heavy rust. 99% heavy rust. heavy rust. 99% heavy rust. 95% heavy rust- 95% heavy rust- 95% heavy rust.

This severe salt spray test again demonstrates the surprising and unpredictable superiority of the compositions containing diamine in contrast to composition A without diamine.

STATIC WATER DROP TEST Test specimens were formed as equilateral triangles from & inch thick carbon steel. Each specimen had an altitude of 1.625 inch and was provided with a central dimple having a spherical radius of .75 inch. In performing the test a specimen was first polished and cleaned, and the corners were bent to form legs. It was then immersed in the material under test with the concave side of the dimple up, and the test beaker was placed for 1 hour in an oven at F. Then the beaker was removed from the oven, a drop of water was placed in the dimple below the oils surface, and the beaker was restored to the oven at 140 F. After 5 days the beaker was again removed from the oven and the extent of corrosion in the dimple observed.

Table IV Composition Appearance after 5 Days Black stain, severe etching. Gra l?) stain, slight etching.

The panel was then immersed horizontally for 15 seconds in a shallow dish containing the above mixture. After draining momentarily the test panel was placed in a humidity cabinet for one hour at 77 F. Thereafter the amount of corrosion was observed visually.

Table V Composition Appearance After 1 Hour Exposure Clean. Do.

As shown in the several tests described above, amounts of diamine as low as 0.4% by weight provide a surprising improvement in the corrosion resistance of metals treated with the coating material of the invention. The only one of the five tests in which 0.4% diamine (B) showed little improvement over composition A was the water displacement and water stability test, wherein results equivalent to the base composition A were obtained. In all five tests 0.8% and 1.6% diamine compositions were far superior to the base composition A.

It will be apparent to those skilled in the art that the compositions described in detail herein may be modified to some extent by the addition of other materials which do not materially affect their basic and .novel characteristics.

For example, successful results have been obtained using compositions as described above which have p,

an isobutylene polymer or an oxidized wax fraction.

Obviously, many modifications and variations of the invention, as hereinbefore set forth, maybe made Without departing frornjhe spirit and scope thereof, and therefore only such limitations should be imposed asare indicated in the appended claims.

We claim:

1. A fluent coating m'aterialhaving property of floating on Water and suitable for application .by water flotation to the inner walls of a metal tank to protect said tank from corrosion; said material being the product of mixing together (a) a mixture consisting essentially of 1 to 5% of tall oil by volume, residual oil from straight run distilling a naphthene base crude oil, said residual oil having a Saybolt-Purol viscosity of 40-55 seconds at 210 F., and sufficient petroleum oil of lower viscosity than said residual oil to thin said residual oil and form a coating material having a Sayboit-Furol viscosity in the range of about 25-50 seconds at 122 F.; and (b) a corrosion inhibiting amount of aliphatic diamine.

2. A fluent coating material in accordance with claim 1 wherein said residual oil constitutes 25-40%, said petroleum oil constitutes 55-70%, and said tall oil constitutes 2-4% of said mixture by volume; and wherein said diamine constitutes 0.4-2% of said fluent coating material by weight.

3. A fluent coating material in accordance with claim 2 wherein said residual oil constitutes about 33.3%, said petroleum-oil constitutes about 63.8%, and said tall oil constitutes about 2.9% of said mixture by volume; and wherein said diamine constitutes about 1.6% of saidfluent coating material by weight.

4. A fluent coating material in'accordance with claim 1 wherein said petroleum oil has a viscosity of about 100-175 seconds Saybolt-Universal at 100 F.

5. A fluent coating material in accordance with claim 1 wherein said diamine has the general formula:

wherein R represents an alkyl group having from 8 to 18 carbon atoms. 6. A fluent coating material in accordance with claim or 5 wherein said alkyl group is derived from-tallow fatty acids.

7. A fluent coating material having the property of floating on water and suitable for application by water flotation to the innei walls of a metal tank to protect.

said tank from corrosion, said material being the product of mixing together tall oil; a corrosion inhibiting amount: of an aliphatic diamine; residual oil from straight-run distilling a naphthene base crude oil, said residual oil- 0 having a Saybolt-Furol viscosity of 40-55 seconds at oil being present in an amount between 1 and 5% by;

volume of the sum of the volumes of said tall oil, said' residual oil, and said petroleum oil. i

8. A fluent coating material in accordance with claim- 7 wherein said residual oil constitutes -40% by volume, said petroleum oil has a Saybolt-Universal viscosity of 100-175 seconds at 100 F. and constitutes 55-70% by volume, said tall oil constitutes 2-4% by volume of said sum, and wherein said aliphatic diamine has the gen eral formula:

wherein R represents an alkyl group having from 8 to 18 carbon atoms, said aliphatic diamine constituting 0 .4-2% by weight of said fluent coating material.

References Cited in the file of this patent UNITED STATES PATENTS 1,850,700 Taylor Mar. 22, 1932 2,286,244 Whitacre June 16, 1942 2,436,599 Read et al Feb. 24, 1948 2,461,971 Fischer 1 Feb. 15,1949 

1. A FLUENT COATING MATERIAL HAVING THE PROPERTY OF FLOATING ON WATER AND SUITABLE FOR APPLICATION BY WATER FLOTATION TO THE INNER WALLS OF A METAL TANK TO PROTECT SAID TANK FROM CORROSION, SAID MATERIAL BEING PRODUCT OF MIXING TOGETHER (A) A MIXTURE CONSISTING ESSENTIALLY OF 1 TO 5% OF TALL OIL BY VOLUME, RESIDUAL OIL FROM STRAIGHT RUN DISTILLING A NAPHTHENE BASE CRUDE OIL, SAID RESIDUAL OIL HAVING A SAYBOLT-FUROL VISCOSITY OF 40-55 SECONDS AT 210*F., AND SUFFICIENT PETROLEUM OIL OF LOWER VISCOSITY THAN SAID RESIDUAL OIL TO THIN SAID RESIDUAL OIL AND FORM A COATING MATERIAL HAVING A SAYBOLT-FUROL VISCOSITY IN THE RANGE OF ABOUT 25-50 SECONDS AT 122*F.; AND (B) A CORROSION INHIBITING AMOUNT OF ALIPHATIC DIAMINE. 